It is desirable in many optical systems to be able to dynamically change the focal length of or effective airspaces in an optical layout. For example, in a camera, it is often advantageous to have a zoom lens that is capable of altering its focal length in order to change the magnification of an image. In other optical systems, such as viewfinders for near-to-eye virtual reality displays, it is beneficial to have a viewfinder that can quickly switch from creating a wide-angle, immersive image to displaying a narrow angle, high resolution image. Implementation of zoom, angle adjustment, and other focal-length dependent dynamic optical alterations typically require mechanical adjustment—an element or optics group is moved in relation to others and the overall focal length of the system is adjusted.
The mechanical adjustment of such systems requires the motion of an element and can thus be adjusted only as quickly as the elements can be moved. The mechanism for such adjustment requires some sort of motor if a computer is to control the adjustment. The attendant size of the adjustment mechanism can be difficult to incorporate into small cameras such as those in mobile telephones or virtual reality displays where weight is often an important factor. Mechanical adjusters are prone to breakage and must be kept clean in order to function well, necessitating the delicate treatment of zoom camera lenses, microscopes, and other equipment optical equipment with mechanically adjusted focal lengths.
Accordingly, it is desirable to provide electrically controlled optical elements and an associated method. The electrically controlled optical elements afford a method for altering an optical system's configuration without physically moving any of the optics, allowing a compact, durable, quickly adjustable optical package.